A weight sensor can be located either on the trailer side or the vehicle side. An electric actuator slide moves forward to raise a load sensor sandwiched between an actuator block and a contact block, through an opening in the bottom of a tube and into contact with a force transfer bar, to load the sensor for determining the weight loaded on it.
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11. A vehicle side weight sensor comprising:
a ball support for connecting a trailer to a trailer hitch, the ball support having a tube arranged behind the ball support, the ball support having a force transfer bar arranged inside the tube, an inside bottom of the tube having an opening;
a load sensor sandwiched between a contact block and an actuator block to support and protect the sensor from damage while in either of two positions, a first position in which the contact block, actuator block and load sensor are not in contact with a bottom of the force transfer bar and a second position in which the contact block, actuator block and load sensor are raised into contact with the bottom of the force transfer bar through the opening in the tube bottom, using an actuator slide, to such a height that weight is transferred from the ball support directly to the load sensor which is sandwiched between the contact block and actuator block.
1. A trailer side weight sensor comprising:
a ball latch for connecting a trailer to a trailer hitch, the ball latch having a tube arranged behind the ball latch, and a force transfer bar arranged inside the tube, both the force transfer bar and the tube being pivotally connected to a trailer so that when the ball latch is connected to the trailer hitch, the force transfer bar pivots to contact an inside bottom of the tube, the inside bottom of the tube having an opening;
a load sensor sandwiched between a contact block and an actuator block to support and protect the sensor from damage while in either of two positions, a first position in which the contact block, actuator block and load sensor are not in contact with a bottom of the force transfer bar and a second position in which the contact block, actuator block and load sensor are raised into contact with the bottom of the force transfer bar through the opening in the tube bottom, using an actuator slide, to such a height that weight is transferred from the ball latch directly to the load sensor which is sandwiched between the contact block and actuator block.
2. The trailer side weight sensor of
3. The trailer side weight sensor of
4. The trailer side weight sensor of
5. The trailer side weight sensor of
6. The trailer side weight sensor of
8. The trailer side weight sensor of
9. The trailer side weight sensor of
a mechanism to connect the load sensor and actuator slide to a source of electrical power;
a computational assembly for determining the weight applied to said load senor; and
a mechanism to display the weight sensed by the load sensor.
10. The trailer side weight sensor of
12. The vehicle side weight sensor of
13. The vehicle side weight sensor of
14. The vehicle side weight sensor of
15. The vehicle side weight sensor of
16. The vehicle side weight sensor of
18. The vehicle side weight sensor of
a mechanism to connect the load sensor and actuator slide to a source of electrical power;
a computational assembly for determining the weight applied to said load senor; and
a mechanism to display the weight sensed by the load sensor.
19. The vehicle side weight sensor of
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This application is a continuation-in-part of application Ser. No. 16/226,981, filed Dec. 20, 2018, which issued Aug. 25, 2020 as patent Ser. No. 10/753,789, which is a continuation-in-part of application Ser. No. 15/016,867, filed on Feb. 5, 2016, which issued Jun. 4, 2019 as patent Ser. No. 10/309,824, which was a conversion from U.S. Provisional Application No. 62/112,440 filed on Feb. 5, 2015, the entire contents of each of which are hereby incorporated by reference.
Not Applicable.
This invention relates to vehicle hitches and in particular to hitches that includes a sensor to provide the user with information on the load applied to the hitch.
Towing a trailer behind a vehicle may be dangerous if the weight of the trailer is improperly balanced or exceeds the intended design of the vehicle. Exceeding the rated towing capacity of a vehicle can result in a very dangerous driving condition in addition to potential damage to the vehicle. For instance, dangerous trailer sway can occur by loading a trailer such that the proper proportions of “tongue weight” to gross weight are not achieved.
However, current technology does not provide an easy or convenient mechanism for measuring the tongue weight of a trailer. In fact, the almost-universally suggested method for measuring the tongue weight of a loaded trailer involves the use of a conventional bathroom scale, a brick, and a piece of wood. Such an awkward and inconvenient method of measuring the tongue weight of a trailer is, unfortunately, the state of the art.
The invention can either be implemented on a trailer side weight sensor or a vehicle side weight sensor. The trailer side weight sensor has a ball latch for connecting a trailer to a trailer hitch, the ball latch having a tube arranged behind the ball latch, and a force transfer bar arranged inside the tube, both the force transfer bar and the tube being pivotally connected to a trailer so that when the ball latch is connected to the trailer hitch, the force transfer bar pivots to contact an inside bottom of the tube, the inside bottom of the tube having an opening. A load sensor is sandwiched between a contact block and an actuator block to support and protect the sensor from damage while in either of two positions, a first position in which the contact block, actuator block and load sensor are not in contact with a bottom of the force transfer bar and a second position in which the contact block, actuator block and load sensor are raised into contact with the bottom of the force transfer bar through the opening in the tube bottom, using an actuator slide, to such a height that weight is transferred from the ball latch directly to the load sensor which is sandwiched between the contact block and actuator block.
The actuator slide is tapered so sliding the actuator slide from the first position to the second position raises the actuator block, load sensor, and contact block to a height above the inside bottom of the tube, through the opening in the tube bottom, so that weight is transferred from the ball latch directly to the load sensor which is sandwiched between the contact block and actuator block. The actuator slide is arranged to move back and forth in-line with the tube, and the actuator is electric and is activated to move back and forth via an app, preferably on a mobile device such as a smart phone.
Power is provided to the load sensor and electric actuator via the wiring adapter which fits a standard trailer connector.
Both the computation and the display of the weight sensed by the load sensor are done by the app and the smart phone.
The vehicle side weight sensor has a ball support for connecting a trailer to a trailer hitch, the ball support having a tube arranged behind the ball support, the ball support having a force transfer bar arranged inside the tube, an inside bottom of the tube having an opening. A load sensor is sandwiched between a contact block and an actuator block to support and protect the sensor from damage while in either of two positions, a first position in which the contact block, actuator block and load sensor are not in contact with a bottom of the force transfer bar and a second position in which the contact block, actuator block and load sensor are raised into contact with the bottom of the force transfer bar through the opening in the tube bottom, using an actuator slide, to such a height that weight is transferred from the ball support directly to the load sensor which is sandwiched between the contact block and actuator block.
Power for the computational assembly 28 can be provided with a hardwired connection to the vehicle's OEM (original equipment manufacturer) wiring harness or via a plug-in connection into the vehicle's electrical system, for example located at the rear of the vehicle; power can also be provided to the computational assembly 28 using an internal power supply, such as a battery, which may be rechargeable, disposable, or of any other suitable variety.
A readout from the at least one load sensor 22, for example via the computation assembly 28, is provided to the operator so that the operator can determine how much load (weight) is placed on the hitch receiver 12 in real time. The readout can be provided to the operator in a variety of ways. For example, as illustrated in
As show in
In some embodiments, the first layer of protective material 24 and the second layer of protective material 26 extent beyond the distal end 36 of the load sensor 22, as shown in
With regard to
The invention is also useful in gooseneck trailer configurations which utilize a “turnover ball” hitch mechanism. In such applications a hitch weight sensing device may be added to obtain the benefits discussed above. Gooseneck hitches such as shown in U.S. Pat. Nos. 6,447,000; 7,775,545, the disclosures of which are incorporated herein by reference, are mounted to the bed of a pickup truck and often allow the hitch ball to be lowered below the floor of the truck to permit full use of the bed of the truck.
In typical “gooseneck” hitches, the truck bed surface 50 has an opening through which a turnover ball 52 may be inserted. While the turnover ball 52 could simply be threaded into the truck bed, it is more typically inserted into an opening 56 formed in the truck bed frame 60. In many arrangements, the frame is an added on unit mounted underneath the truck bed. In any event, the turnover ball 52 is inserted into the formed opening 60 and is typically secured with a pin (not shown) through a side opening 62 in the turnover ball and through the truck frame. This secures the turnover ball 52 from being removed unless intended. The opening 56 may include a load force assembly 66 which is inserted into the opening and held in place by upper limiting tabs 68 or the like. An opening 70 is formed for the pin to pass there through when secured to the turnover ball side opening 62.
At the bottom 72 of the load force assembly a load sensor 74 is positioned. It may be protected by layers of protective material on one or both sides as discussed previously. Appropriate wiring 76 carries the signal to a computational assembly 80 for processing which is then transmitted via an OEM wire harness, Bluetooth, Wi-Fi or other means to be displayed in the vehicle with an in-cab display, phone screen or separate display. The load force assembly 66 is placed beneath the removable “turnover” ball on the weight bearing surface of the retention mechanism 82 designed to secure the turnover ball 52.
The retention mechanism 82 is attached to the frame of the vehicle.
Trailer loads transmitted through the Gooseneck trailer configuration to the turnover ball mechanism in the vehicle will be measured and communicated to the user
Load Force Assembly 66:
Power may be provided to the “computational assembly” from the vehicle's electrical system in four ways:
The computational assembly 80 that provides the means to determine loads transmitted from the load force sensors 74 and send them to various users' locations. i.e. drivers cab, rear bumper, or to a person operating an independent piece of equipment loading the trailer. It can be transmitted via either OEM wire harness, Bluetooth, Wi-Fi, or other electronic means. These signal can be displayed electronically on the vehicle's OEM in-cab-display, Smart phone screen, or separate display specifically designed for use with the invention. All means allow the user to view the actual load on the trailer hitch in real-time.
Load Force Assembly Method 1:
Load Force Assembly Method 2:
In some embodiments, the first and second layers of protective material 24, 26 are made from a metallic material, for example sheet steel or stainless steel. In some embodiments, the protective material thickness is increased specifically over the load sensor 40 to ensure accurate load force transfer. The first and second layers of protective material 24, 26 are secured to one another along their edges to prevent movement of the load sensor 22 within the load force assembly 20. The first and second layers of protective material 24, 26 can be secured to one another in any suitable way, for example adhesively, rivets, spot welding, welding, etc.
In some embodiments, the first and second layers of protective material 24, 26 are made from a durable fabric material, for example epoxy impregnated Kevlar® brand aramid fiber, fiberglass, or carbon fiber. In some embodiments, the protective material thickness is increased specifically over the load sensor 40 to ensure accurate load force transfer. The first and second layers of protective material 24, 26 are secured to one another along their edges to prevent movement of the load sensor 22 within the load force assembly 20. The first and second layers of protective material 24, 26 can be secured to one another in any suitable way, for example adhesively, thermal set epoxy, etc. One or both of the protective layers of material can further be made from any suitable material or combination of materials, alloys, composites, etc.
In some embodiments, the load force assembly 20 can be used with any class of hitch receiver 12, for example class I & II, III & IV, V, and VI.
In some embodiments, the load force assembly 20 is integrated into the hitch receiver 12. In some embodiments, the load sensor 22 is integrated into the ball mount 34 on its underside. In this way, an existing hitch receiver 12 would not need to be modified since the load sensors 22 can be on the ball mount 34. In some embodiments, the load sensor 22 is located on the inside surface of the hitch receiver tube 32 and a layer of protective material is placed over the load sensor 22 such that the ball mount 34 can be located on top of the layer of protective material.
In some embodiments, the load force assembly 20 can be used as an aftermarket product or with an OEM hitch receiver 12. In some embodiments, the load sensor 22 can be used as an aftermarket product or with an OEM hitch receiver 12.
In some embodiments, the at least one load sensor 22 is a “FlexiForce™” sensor from Tekscan, Inc. of South Boston, Mass. Such sensors are described in U.S. Pat. Nos. 6,272,936 and 7,258,026, the disclosures of which are incorporated herein by reference.
The load sensors 22 provide an output from a load which needs to be converted to a value in pounds or kilograms. There are two main steps for this conversion. Step one is to compensate for the time-drift of the sensor. To do that we averaged several empirical measurements on different sensors to determine a “typical” drift curve. Those curves were taken under constant load, and the values are raw sensor values vs. time. Then we approximated that measured curve with a piecewise linear compensation function. The compensation function is subtracted from the raw sensor value in the smartphone before converting it to a weight.
The compensation function may be a single fixed function of time, representing an average over the sensors and conditions. It may also be a function of both weight and time and instead of being based on a piece-wise linear curve may be a polynomial whose coefficients are dependent on weight.
Next, the drift-compensated sensor value is converted to weight. For the sake of clarity, let's use the terms compensation (to remove time drift), conversion (from compensated signal to weight) and calibration (which generates input to the conversion formula). The need to apply linearization during this conversion step is pretty standard in any sensor measurement. As above, a 3-parameter polynomial may be used to make this conversion, but the coefficients may be measured during production so they are unique for each sensor. The coefficients will reflect the shape of the curve, and they may be scaled or otherwise manipulated to take into account the user calibration.
The computational assembly may do the math itself prior to sending the weight to the smartphone. Conversely, it may be done in an app on the phone so a) the calibration factors do not need to be sent from the phone down to the device, and b) the phone more readily deals with a situation where power is interrupted to the sensor during a measurement.
The graph in
The graph in
In the Compensation block the drift is corrected using the formula shown, where xi is the input signal, xo is the output signal, and they ak's are coefficients determined during the two calibration steps. At the output of this block, the signal is as represented by the red trace in the graph above.
In the Conversion block the signal is converted from units of millivolts to units of pounds or kg using the formula shown. Again xi is the input signal, xo is the output signal, and they ak's are coefficients determined now during only the user calibration. The scope of these variable names is local to the block, i.e. the ak's here are not the same as the ones in the compensation block. The output value xo here is what is displayed on the smartphone app (or other user interface).
The geometry of the “ball support” plays the most influential role in determining the force being applied into a vehicle's hitch system.
For example;
1) the length of the ball support (or mount) that is inserted horizontal into the vehicle's receiver tube from the end, changes the force applied at the point of contact between the two. Point of contact occurs inside near the end of the vehicle's receiver tube.
2) in the opposite direction, the horizontal distance from the end of the vehicle's hitch tube to the center of the “ball” dramatically changes the force applied at the point of contact between the two.
These two factors seem to mandate that prior art trailer tongue weighing systems must maintain these two factors in order to calculate accurate weight determinations.
Applicant's system doesn't have to control these two factors because of the sandwiched position of the sensor and by having a User calibration system that is performed before every use. It is quick, easy and automatically takes into consideration all of the real-time influences of changing geometry that is inherit in the many ball supports of the market place. This has never been available to the market place to date.
This allows the user of the inventive system the exclusive ability to use all makes models and sizes of ball mounts they currently own or may wish to buy in the future.
The graph in
In each form of the invention, the standard trailer hitch and the gooseneck hitch in pickup beds, the load sensors detect the downward weight on the hitch and can display it so the user can act accordingly. If the weight is within limits nothing needs to be done and the user has the assurance that their weight is acceptable. If not, weight can be removed or adjusted on the trailer to decrease the tongue weight.
Another embodiment of the invention is designed to permanently install the load sensor in the hitch receiver tube. In this embodiment, the hitch receiver tube 100 has a bottom surface 102. Below the bottom surface of the hitch receiver tube 102 is a contact block 104, an actuator 106 and an actuator slide 108. The load sensor 110 is arranged on the top of the actuator 106. Actuator 108 is tapered and can slide from right to left, from an unengaged position to an engaged position. As the slide 108 moves to the left, the larger cross-sectional portion raises the actuator 106 and contact block 104 above the bottom surface of the hitch receiver tube 102. When the ball mount is installed into the tube receiver 100, the weight loaded on the ball of the ball mount is transferred to the load sensor, which can determine the weight.
A trailer side weight sensor embodiment is shown at
Referring to
Referring to
Referring to figures
This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.
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